diff --git a/driver_library/include/ethosu.hpp b/driver_library/include/ethosu.hpp
index eaa1ce7..27f6828 100644
--- a/driver_library/include/ethosu.hpp
+++ b/driver_library/include/ethosu.hpp
@@ -235,7 +235,7 @@
     virtual ~Inference() noexcept(false);
 
     bool wait(int64_t timeoutNanos = -1) const;
-    const std::vector<uint32_t> getPmuCounters() const;
+    const std::vector<uint64_t> getPmuCounters() const;
     uint64_t getCycleCounter() const;
     bool cancel() const;
     InferenceStatus status() const;